Device for producing and treating thin liquid films



1 0a, 4, 1932. v. c. BENJAMIN 1,881,041

DEVICE FOR PRODUCING AND TREATING THIN LIQUID FILMS Fild March 30. 1929, 2 Sheets-Sheet 1 FIGJ- VICTOR C. BENJAMIN lNl/E TOR v A T TORNEY Oct. 4, 1932. v. c. BENJAMIN DEVICE FOR PRODUCING AND TREATING THIN LIQUID FILMS 2 Sheets-Sheet 2 Filed March 30, 1929 FIGZ VICTOR C. BEMMM/N ATTORNEY VICTOR C. BENJAMIN, OF L08 ANGELDS, CALIFORNIA DEVICE FOR PRODUCING AND TREATING THIN LIQUID FILMS Application filed larch so,

' An object of my invention is to reduce a liquid to the physical condition of a moving film of substantially uniform thickness, in which condition it may be subjected to the action of heat, of vapors, of gases or of liquids. A further object of my invention is to so distribute the liquid over a solid surface that all parts of the liquid body may be subjected in an equal and uniform degree to the action of heat, evaporation or chemical reaction. Further objects and advantages of my invention will be evident from the following description of illustrative embodiments thereof, taken inconnection with the attached drawings in which,

Fig. 1 is an illustration in vertical cross section of a modification of my device suited I to the evaporation, fractionation or reduction of simple or mixed liquids and to the treatment of liquids with gases or vapors.

Fig. 2 is a similar illustration of a modification of my device suited to the treatment'of one liquid by another.

Referring to Fig. 1, 10 is a hollow metallic casing part y closed at each end. 11 is a hollow cylinder of porous or equivalent material, the nature of which will later be described in more detail. This cylinder may '80 be retained in the position shown by means of a groove 12 in the lower portion of the shell 10, and by means of a screwed ring 13 containing a similar groove and screwed into .a corresponding thread in the upper end of the shell 1O.

Surrounding the upper end of this shell is a cap 14 which is removably attached to the upper end of the casing as by means of bolts not shown. At the lower end of the easin a flattened annular chamber 15 is formed, this chamber communicating with the interior of the porous cylinder 11 by means of the annular opening 16. The interior of the orous cylinder also communicates with the interior of the cap 14 by means of the annular opening 18.

Below the chamber 15 a second and smaller chamber 19 may be formed, this chamber also communicating with the interior of the porous cylinder through the annular opening mixture of sand or of diatomaceous earth,

1929. Serial N0. 351,317.

20 and the annular opening 16 above described.

Situated centrally within the porous cylinder and made fast in any convenient manner to the cap 14 and also to the bottom of thecasing below the chamber 19, is a heating element 21. As shown in the drawings this heating element is a metallic. tube through which passes fire gases generated in the fire box 22 by means of a flame produced by the burner indicated at 23. This fire box, as indicated in a purely conventional manner, consists of a tight metallic casing 24 made fast to the lower end of the heating tube 21 and lined with fire brick or tile 25. The fire gases generated in this fire box are discharged from the upper end 26 of the heating element.

It will be understood that the heating element may be a tube heated by fire gas, or by steam, or it may be an electrical resistance element with or without a metallic casing, or it'ma'y be any other of the well known means for producing or conveying heat in or into the interior of a substantially closed vessel, and I do not limit myself to any particular means for producing or transmitting heat.

The main casing 10 is provided with a pipe connection 27, the upper cap 14 with a pipe connection 28, the lower chamber 15 with a pipe connection 29 and the lowermost chamber 19 with a pipe connection 30.

In small sizes the porous cylinder 11 may be made of a single piece of unglazed earthenware, such as is used in water filters or for the inner cells of wet batteries. In larger'sizes it may be a cylinder of neat Portland cement, or of cement with an adaccording to the degree of porosity desired. For still larger sizes, where it is desired to expose a considerable surface to the action of heat, evaporation, or chemical reaction, the porous cylinder may consist of a skeleton framework, such for instance as that used in making sidewalk lights, in approximately cylindrical form, with plates of earthenware, porous brick or tile, cement or other suitable porous material sealed into the openings of 100 the frtmework. It is also possible to substitute for a porous cylinder a cylinder composed of very heavy wire mesh cloth, so tightly woven or rolled that the interstices represent only a 'very small portion of the superficial area or a stack of spaced rings of sheet metal such as are used in construction of'edge filters, or even a cylinder of slotted screen provided only that the slots are horizontal in position and have a'r'elatively very small area.

The requirements for the porous cylinder are: first, that it shall have sufiicient porosity to pass the amount of liquid required at the preferred pressure; second, that it shall not be effected by-the heat or by the reagent used in the treating process, whatever this may be; third, that it be reasonably staunch and free from excessive liability to accidental breakage; fourth, that it be capable of being sealed at its ends against leakage, as at the points indicated at 12and 13in the figure. In the particular construction shown in the figure a ring of soft packing, as of shellacked asbestos paper or similar semiflexible material would be placed in the bottom of each of the grooves and the screwed ring drawn up tightly enough to place this packing in compression. In units of larger size various mechanical means, which are well known and understood, may be used to produce a liquidtight seal between'the ends of the porous cylinder and the surrounding casing.-

In using this device for the distillation of mixed liquids, I proceed in the following manner: v

The annular chamber31 between the outer casing 10 and the porous cylinder 11 is filled with the liquid to be distilled by means of the pipe 27, which communicates with a source of supply and a means, not shown, for producing a flow stream of li uid under pressure. The pressure thus maintained in the annular chamber 31 forces the liquid through the pores of the porous cylinder 11 and causes it to extrude through such pores onto the interior of the cylinder, where it forms a film which is immediately'carried downward in the form of a very thin flowing sheet by gravitation. While this sheet is in motion, which will be solong as a supply of liquid under pressure is maintained 1n the outer chamber 31, it is subjected to the action of heat radiated from the heating element 21, which element in turn is brought to the desired temperature by controlling the fire within the fire box 22, or by controlling the amount of current if an electrical heating element be used. The heat radiated from the heating element acting on the flowing film causes the evaporation of a desired proportion of the liquid. The vapors thus generated pass upward through the opening 18 and through the pipe 28 to a condenser or other means of disposal not shown.

Such proportion of the liquid as is not evaporated during this treatment flows downwardly through the opening 16 to the chamber 15, from which it flows throu h pipe 29 to a point of storage or other disposition not shown. This pipe may be rovided with a regulating valve or prefera ly with a U bend to act as a liquid seal and to prevlent the downward passage of vapors through t is pipe.

If it is desired, as is usually the case, to conduct the distillation in an atmosphere of steam, such steam may be admitted to the apparatus through the pipe 30, through which it enters. the lowermost chamber 19, passes upward through the opening 20 and sweeps the interior surface of the liquid film, thereby removing vapors as fast as formed and passing out with them through pipe 28.

I do not restrict my device to the form or proportions shown, as obviously it would be desirable to make the tubing, casing and heating element very much longer in proportion to their diameter than here shown.

Furthermore, I do not restrict myself to a cylindrical device, as while a substantially cylindrical form is desirable because of its much greater resistance to outside pressure, my device could feasibly be constructed, particularly in large sizes, in a polygonal form, or even With large flat porous plates, provided only that the latter were sufliciently supported against the pressure of the liquid agalnst the entering side.

Further, such fiat plates need not be set in a vertical position (as a cylinder must be) but may be fixed at any angle to the horizon at which the material to be treated will flow from the upper surface.

A cylindrical device also might readily be so arranged that the heat would be applied from the outside and the oil passed through the porous cylinder from the inside to the outer surface, which would then be the heated surface.

The apparatus may also be used as indicated in Fig. 1 for the treatment of a flowing film of liquid by means of a heated gas or vapor, or a chemically reactive gas or vapor. In such case the treating fluid would be introduced through the pipe 30 and would make its escape through the pipe 28, while the liquid to be treated would be introduced through the pipe 27 and would make its escape through the pipe 29.

For the treatment of one liquid with another I prefer to use the modified form illustrated in Fig. 2, which is practically an inversion of Fig. 1.

Referring to Fig. 2, 10 is the hollow metallic casing, 11 the porous cylinder, 12 and 13 the lower groove and the upper groovering, 14 the uper cap and 27 the pipe for admitting the liquid to be treated, under pres- 37 is provided for draining any water condensing in the cylinder 32.

Between this cylinder and the interior of the porouscylinder 11'there is left an annular space 38 comm nicating at the top through an annular opening 39 with the interior of the cap 14, which cap is provided with a ventpipe 40. Space 38 also communicates at its lower end through an annular opening 41' with the interior of a shallow chamber 42 formed on the lower end of the shell 10,this chamber being provided with a drain pipe 43 controlled by a valve 44.

Centrally located over the upper end of thecylinder 32 is placed a shallow bell 45 to the upper part of which is attached a pipe 46 controlled by a valve 47, this pipe .passing through and being aflixed to the cap 14 4 at any convenient point and communicating with a source of supply of the treating liquid.

The pipe 27 communicates with a source of supply of the liquid to be treated, and is controlled by a valve 48. 7

Assuming the treating liquid to be heavier thanthe liquid to be treated, which is almost always the case, this apparatus functions as follows: 7

Valve 48 being open, the liquid to be treated is introduced under pressure through pipe 27 into the annular chamber 31, thence passing through the pores of the porous cylinder %1 and forming a film on its interior surace.

On opening valve 47, valve 44 being closed, treating liquid is introduced to fill the chamber 42 and the annular space 38, but should not be allowed to fill the cap 14 nor to overflow through the vent pipe 40.

-The feed of liquid to be treated through pipe 27 being continued, the film continuously produced on the interior surface of the 50 ,porous cylinder 11 will travel upward in contact with the mass of treating liquid contained in the annular space 38, will fill the interior of the cap 14, and finally overflow through vent pipe 40, whence it may be conducted to any convenient point of storage or use of treated liquid. The treating liquid in tion of acidified petroleum rous cylinder 11 and to cause it to counterflow the ascending film of liquid to be treated. A

secondary function, for c linder 32 is that of a heating means, where 1t is desired to supply heat to the treatment. To reduce this function valve .35 is opened, an water condensing inside the cylinder is drained out by means of valve 44.

The a paratus above described is adapted to a wi variety of uses in which desirable results are produced by intimately contacting one li uid with another liquid immiscible therewith. Examples are: the neutralizaroducts with aqueous solution of alkalis; t e solution of tar acids from coal tar oils b aqueous alkaline solution, and the remova of naphthenic soap from neutralized petroleum products by washing with hot water. The process described is extremely advantageous in all cases where extreme intimacy of contact between the two liquids is required while agitation, which often results in the formation of emulsion between the two liquids, is to be avoided.

I claim as my invention:

1. Ap aratus for producing and treating flowing lms of li uid, comprisin :a sheet of substantially rigi material uni ormly permeable to a liquid but oflering substantial resistance to its passage therethrough; means for applying said liquid under pressure to one side of said sheet to cause said liquid to pass slowly therethrough, said sheet being fixed in a substantially vertical position so that said liquid as it ermeates said sheet will flow thereover in a lm of substantially uniformthickness, means for continuously contacting a fluid with said flowin film and means for heating said fluid an said film during the contact. p

2. Apparatus for producing and treating flowing films of liquid, comprising: a sheet of substantially rigid material uniformly permeable to a liquid but ofiering substantial resistance to its passage therethrough; means for applyin said liquid under pressure to one side 0 said sheet to cause said liquid to pass slowly there through, said sheet being fixed in a substantially vertical position so that said liquid as it permeates said sheet will flow thereover in a film of substantially unifoi'm thickness; means for applying heat to the side of said film opposite said sheet and means for simultaneously contacting a fluid therewith.

3. Apparatus for producing and treating flowing films of liqu d, comprising: a sheet of porous material ofi'ering substantial resistance to the passage of liquid therethrough; means for applying said liquid under pressure to one side of said sheet to cause said liquid to pass slowly therethrough, said sheet being fixed in a substantially vertical position so that said liquid as it passes through said sheet will flow thereover in a film of substantially uniform thickness means for continuously contactmg a fluid with said flowing film and means for heating said fluid and said film during the contact.

4: Apparatus for roducing and treating flowing films of liquld comprising: a sheet of porous material offering substantial resistance to the passa e of liquid therethrough; means for a p ying said liquid under pressure to one si e of said sheet to cause said liquid to pass slowly therethrough, said sheet being fixed in a substantially vertical position so that said liquid as it passes through said sheet will flow thereover m a film of substantially uniform thickness; means for applying heat to the side of said film opposite said sheet and means for simultaneously contacting a fluid therewith.

5. Apparatus for producing and treating flowing films of liquid, c omprisingz a cylinder of substantially rigid material uniform- 1y permeable to a liquid but offering substantial resistance vto its passage therethrough, said cylinder being fixed in a substantially vertical position;.means for applying said liquid under pressure to one surface of said cylinder to cause said liquid to pass slowly therethrough and to form a flowing film of substantially uniform thickness on the opposite surface, and means for applying heat to the free surface of said flowing film.

6. Apparatus for producing and treating flowing films of liquid, comprising: a cylinder of substantially rigid material uniformlypermeable to a liquid but ofl'ering substantial resistance to its passage therethrough, said cylinder being fixed in a substantially vertical position; means for ap lying said liquid under pressure to one surface of said cylinder to cause said liquid to pass slowly therethrough and to form a flowing film of substantially uniform thickness on the opposite surface, means for continuously contacting a fluid with said flowing film and means for heating said fluid and said film during the contact.

7. Apparatus for producing and treating flowing films of liquid, comprising: a cylinder of substantially rigid material uniform- 1y permeable to a liquid but offering substantial resistance to its passage therethrough, said cylinder being fixed in a substantially vertical position; means for applying said liquid under pressure to one surface of said cylinder to cause said liquid to pass slowly therethrough and to form a flowin film of substantially uniform thickness on t e opposite surface; means for applying heat to the free surface of said film, and means for simultaneously contacting a fluid therewith.

8. Apparatus for producing and treating flowing films of liquid, comprising: a cylinder of porous material offering substantial resistance to the passage of liquid therethrough, said cylinder being fixed in a substantially vertical position; means for applying said liquid under pressure to one sur ace of said cylinder to cause said liquid to pass slowly therethrough and to form a. flowing film of substantially uniform thickness on the opposite surface, and means for-applying heat to the free surface of said flowing film. v

.of said cylinder to cause said liquid to pass slowly therethrou h and to form a flowing film of substantia ly uniform thickness on the opposite surface, means for continuously contacting a fluid with said flowing film and means for heating said fluid and said film during the contact.

10. Apparatus for producing and treating flowing films of liquid, comprising: a cylinder of porous material offering substantial resistance to the passage of liquid therethrough, said cylinder being fixed in a substantially verticalposition 'means for applying said liquid under pressure to one surface of said cylinder to cause said liquid to pass slowly therethrough and to form a flowing film of substantially uniform thickness on the opposite surface; means for applying heat to the free surface of said film and means for simultaneously contacting a fluid therewith.

I11 witness that I claim the foregoing I have hereunto subscribed my name this 23rd day of March, 1929.

VICTOR C. BENJAMIN. 

